second monitor keeps shutting off

I have a computer with two monitors attached. The second monitor just randomly goes black and my computer makes a sound like I have just disconnected something. All I have to do to fix it is go to screen resolution and tell it to detect the monitor again but it's really annoying that it keeps doing it. I went from a 22 inch samsung lcd to a 24 inch asus and have the same problem. I have also changed video cards.

By any chance are you using the same monitor cable? Power cord? One of these wires could be bad, probably at the connector.

Another possibility, is your power supply sufficient to power your video card with the stress of both monitors? Not just in total wattage matters, but also how many 12V rails and what Amperage on each (You may have say 36Amps total on your 12V rails, but if you have 2 rails with 18A each and your video card needs say 25Amps, then it will be starved for power because it's power is supplied from one of those rails).

If these two check out good, monitor your GPU's temperatures, if it spikes just before it cuts out, it could be a overheating issue on the graphics card. You might be able to increase the card's fan speed, but you just may have an airflow problem through your case (too many fans, too few, wrong placement or wrong direction).

Post all spec's to be sure we have enough info to actually help. Include make/model (or components details), Video card make and model, power supply make, model, and all ratings.

Power supply: Antec 430 wattCpu: Intel Q2 QuadGpu: Geforce Gt 240Memory: 4 Gig DDR 3Window 7 32 bitHard drives: Intel 40 gb ssd and 500gb backupJust one dvd driveThe GPU runs between 50 to 60 CEach core on the cpu stays between 35 to 45 CI am running from the HDMI to the led monitor and from the vga to a 17 inch crt. In the past, I ran the DVI to the monitor and had the same problem. The video card is just a few months old but I guess that doesn't rule it out. I have searched tons of forums for the answer and this was the most informative and best answer that I have seen yet...... Unfortunately, it's still doing it. I really appreciate any help I can get.Thanks

I still suspect your power supply as the problem, but it is possible you have a bad graphics card. Here is why I think your problem comes from your power supply. One source I use when purchasing a product is the tech info and the customer reviews on New Egg and Tiger Direct and this is what I found on your products. The power supply may have 430Watts but your 12Volt supply is on two rails that have 17Amps on each. Your video card's minimum requirements are only 350Watts (system), but 18Amps on that rail which you do not have. (Your motherboard has more reserve than it needs, but your video card is being starved.) Then on the reviews, I see many have problems with this power supply, but one indicates that it is enough for his system but it does not actually deliver the rated Wattage during a stress test. In conclusion, if you can borrow a different power supply, you can test this but I would recommend purchasing a better PS, look for one with more like 500+ Watts [edited/corrected] but mainly with all of the 12Volts on one rail. Look to these two sites for the tech info and for other consumer reviews.

I just bought and installed a corsair 600 watt psu with a single 40w rail and it still has the same problem. I actually am glad to know that my other power supply was good though, because I like to have enough extra computer parts to build another computer if I need to.Thanks

I have a somewhat similar problem, but with only one monitor.I'm wondering if your monitor still goes black when it is the only monitor attached.

I'm also wondering when it goes black. Mine has mostly done that during the firstfew minutes after Windows 7 64-bit or Ubuntu starts. It never happens when DOSis booted from a floppy. The behavior changed a few days ago, going black duringPOST after a restart, but that might be a separate, new problem.

The information on Computing.Net is the opinions of its users. Such
opinions may not be accurate and they are to be used at your own risk.
Computing.Net cannot verify the validity of the statements made on this
site. Computing.Net and Compnet Ventures, LLC hereby disclaim all responsibility
and liability for the content of Computing.Net and its accuracy.